keyboard case charging but not typing

[theResonant]

I followed the instructions here: https://xff.cz/git/pinephone-keyboard/tr...E.flashing

I've opened the keyboard, soldered a USB cable to its PCB then flashed the firmware again (probably not necessary). Then I tested it with the `ppkb-usb-debugger` utility. Interestingly, the keyboard does work, it reacted to the key presses.

Now I need to figure out why won't the phone detect the keyboard. It's either a software issue, or I somehow physically broke the I²C connection. I'll try booting into something else.

[_radv_]

It's a software or OS distribution issue. I plugged my keyboard in while running archlinux minutes ago and it recognizes the keyboard presses, and seems to(?) recognize the charge amount. I'd tried it with other operating systems and it did not work.

[theResonant]

I ended up ordering a new PPKB. The new one works perfectly, the old one doesn't. In my case it looks like it's a physical issue (I'm on postmarketOS). I'll try to debug the old one anyway.

[zltpxqhp69o2]

In my case, I have figured out software configuration, but it is now the second keyboard case that keeps the battery functionality but loses the typing ability after a bit less than a year. It definitely looks like phyically wearing out some connection or cable… Has anyone succeded to figure out the repair?

[grump_fiddle_reinstall]

I ended up ordering a new PPKB. The new one works perfectly, the old one doesn't. In my case it looks like it's a physical issue (I'm on postmarketOS). I'll try to debug the old one anyway.

Did you ever get round to debugging your keyboard unit? Mine has just stopped typing on both a PinePhone and a Pro. So I doubt that it is a driver issue.

I replaced the circuit board earlier this year after an overheating issue when charging the summer before and all seemed to be well after that. Maybe I should just order another circuit board.

Running Mobian on both phones.

---

I just ran sudo dmesg | grep key

[    0.289617] Initialise system trusted keyrings
[    0.300614] Asymmetric key parser 'x509' registered
[    2.515438] input: gpio-keys as /devices/platform/gpio-keys/input/input0
[    3.345855] arm_scpi: module verification failed: signature and/or required key missing - tainting kernel
[    3.586007] pinephone-keyboard 2-0015: Found firmware version 1.0 features 0xf
[    7.217923] systemd[1]: Starting keyboard-setup.service - Set the console keyboard layout...


This is a different result when compared to an earlier post in this thread where the keyboard was not found.

[grump_fiddle_reinstall]

In my case, I have figured out software configuration, but it is now the second keyboard case that keeps the battery functionality but loses the typing ability after a bit less than a year. It definitely looks like phyically wearing out some connection or cable… Has anyone succeded to figure out the repair?

Are there other channels (than this forum) where this issue has been raised and discussed?

I would really like to get a couple of PinePhones with keyboards for junior members of my family, but there is no point doing this if the keyboards only last a year before failing.

[theResonant]

In the meantime, my second PPKB has stopped typing, just like the first. It appears to have happened after detaching / reattaching the phone to the keyboard case a few times.

But I returned to the old PPKB, which I had previously opened and exposed its mainboard and did the following:

1. detached the phone from the PPKB
   
2. soldered an USB connector on the mainboard USB contacts
   
3. connected to the computer (`dmesg -ew` reported it being connected)
   
4. used Megi's tools to flash the stock firmware via USB
   
5. disconnected the USB from the computer (it's still soldered to the mainboard)
   
6. reattached the phone to the PPKB
   
7. reloaded the PPKB kernel module (this works instead of rebooting)
   
8. PPKB did not work
   

HOWEVER, if I keep the USB plugged into the computer, while the PinePhone is attached to the keyboard, THE KEYS WORK. I don't know if flashing did anything (probably not). If I unplug the USB from the computer, the PPKB stops working. But if I plug the USB into the computer again THE PPKB START WORKING AGAIN.

So currently, I can type on the PPKB as long as its mainboard is hardwired to a USB connector and plugged into the computer 

I'm almost certain this had nothing to do with flashing. Resetting the MCU doesn't help either (either via I²C or via USB).

But it's almost certainly a software / firmware issue, because plugging the PPKB into the computer via USB makes it suddenly work again (after reloading the kernel module, but only once).

[theResonant]

After more debugging, I have more questions than I have answers.

The PINE64 Wiki says that the PinePhone powers the PPKB via the POGO pins, specifically via the USB-5V pin. But this pin doesn't seem to be connected to anything on the PPKB mainboard. I checked the schematics, it's supposed to enter the junction pad J2, but J2 has 6 input pins and only 4 wires connect to it (USB-5V isn't one). I also checked with the multimeter, it seems like there's no connection...

However, the MCU seems to work on the 3.3 V that's provided by the USB debugging connection (the one I soldered to the mainboard). When not connected to USB, I can't seem to figure out on the schematics where is the 3.3 V supposed to come from and be provided to the MCU.

But the MCU never wakes up unless powered via the USB debugging connection. This seems to be the core issue. Having the battery connected to the mainboard doesn't work. Having a USB-C cable provide power on its charging port also doesn't work.

I also cannot tell whether the TXS0104ED chip has any role in powering the MCU. I don't think it's supposed to.

I'm convinced someone more knowledgeable could easily decipher all these issues...

[theResonant]

After EVEN MORE debugging and making sense of the schematics, here's what it looks like:

The TXS0104ED chip isn't supposed to provide power to the EM85F684A microcontroller unit (MCU).
However, they both share the same V33 input of 3.3 volts, coming from the ME6206 voltage regulator, a tiny chip on the mainboard.
Moreover, the 3.3 V input coming from the USB debugging pads is also connected to V33.

And it looks like the ME6206 is faulty. This is why the MCU is off all the time, unless powered via the USB debugging pads, which provide the power directly, after the ME6206. At least this is what it looks like to me. I hope I'll get the chance to order an equivalent replacement for the ME6206 and solder it to the mainboard.

In the meantime, I also ordered a new mainboard from PINE64... At least it's not an entire PPKB.